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781.-SWIFT-WAY 7 WKA No. 1735.03 January 3, 1995 Page 2 The proposed wells will be drilled"using a truck-mounted drill rig, equipped with hollow-stem augers to an approximate depth of 55 feet below site grade. Well installation permits will be obtained from the San Joaquin County.Public Health Services prior to drilling the monitoring j wells. Prior to drilling monitoring well MW-4 located in the Stockton Street right-of-way, a City of Stockton revocable permit and encroachment permit will be obtained. Soil samples will be collected from the well borings at five-foot maximum intervals-with a modified California sampler equipped with clean, two-inch diameter, six-inch long brass tubes; samples and drill cuttings will be described in the field by an experienced staff engineer or geologist using the Unified Soil Classification System (USCS). Soil generated during the drilling process will be placed in sealed and labeled, 55-gallon drums and stored on site. . The sample tubes will be sealed with Teflon sheets and plastic end-caps to reduce volatile hydrocarbon loss. The samples will be screened in the field using a photo-ionization detector (PID) to evaluate potential hydrocarbon content. Selected soil samples will be stored on ice in an ice chest and submitted under chain-of-custody documentation to a California-certified laboratory for analysis of Total Petroleum Hydrocarbons (TPH) using Modified EPA test method 8015, and Benzene, Toluene, Ethylbenzene, and Total Xylenes (BTEX) using EPA test method 8020. The wells will be constructed using four-inch diameter, flush-jointed, Schedule 40 PVC casing; 0.02-inch slotted casing will be used for the screened interval. Number 3 sand will be placed in the well annulus as a filter pack. The'filter pack will extend from the bottom of the screened interval to approximately two feet above the top of the screened interval. A minimum two-foot thick bentonite seal will be placed in the well annulus above the filter pack. A grout seal consisting of Portland Cement and bentonite slurry will be tremied into the well annulus above the bentonite seal. The wells will be completed with locking well caps and flush-mounted, traffic-rated well covers. A diagram showing construction details of a proposed ground water monitoring well is shown on Plate 3. WALLACE•KUHL R-y&dprpe. &ASSOCIATES INC.